
So somebody could approach you and fool you without correcting you and you'd be okay with that. JH has been used for his appeal his entire life by his aunt wanting to use him for validation from his grandfather and now the person he fell for (even though DH does like him back now) turned up to be leading him on just so he could be analysed. Like I like DH but he fucked up, there's no misunderstanding DH was interested in JH's behaviour and went along with JH's delusions so he could get what he wanted. He knew it was wrong yet somehow the person used for his image shouldn't be upset? JH whole issue with people stems from the fact that they use him for his potential and that is objectively worst than being used for money or sex because it really was never about you or what you can provide. It's just about what they can use your image as disregarding you like some experiment which is very dehumanising so yeah, he is very validated for being reasonable hurt that someone he thought he could actually be himself with was just another individual who wanted him to be their unwilling muse.

Don't get me wrong DH has his issues but he's not an idiot. His issues aren't JH's and far as I know, JH hasn't shared his issues with DH either so how are they supposed to help each other?? DH knew what he did was wrong which is why he avoided telling him, so whether or not he made progress he undid it himself because he chose to be deceitful and that's not on JH, that's all on him.

He stopped doing it the second he realized it was wrong. He didn't plan on telling him out of self-preservation of his relationship can you blame him? do you think if you were in his position where everyone has left you behind or were treating you like a pariah you would want to lose that one relationship you gained? Even if it was by mistake. Not only that but you're acting like Dohu said he liked him in terms of going out when he never did Juheon did a lot of misunderstanding with the things Dohu said. This doesn't excuse the pain Dohu caused Juheon by not being upfront but I still don't think you can blame this whole thing on Dohu with everything we know so far about his past.

Did I say JH should not be upset? I did not say that. What I'm questioning is the level of upset JH has. If I remember correctly, JH knows that DH has difficulty with expressing and analyzing people. JH could have inquired what is the end game for what he read or if DH was ever genuine with him the entire time they were together, or it was all for that project he was doing.
If that talk happened right after he saw the pc, I would have understood his behavior, but it's been a week. To me, it felt like he didn't try to save the relationship by thinking back the times DH was truthful with him and if he wasn't sure, he could have asked.
As for your very first sentence, it depends what I'm being fooled for, weigh it out and inquire what's the end game. Benefit of the doubt until everything is laid out in the open. DH knew it was wrong, given what JH has told him, but he also weighed it out whether it was worth telling, what was the harm and purpose of his project.

At most, DH knows his issues with his parents, bad relationship with them and that he doesn't like being used. That's why DH got the hint that he was technically doing the same thing. But again, this could have been resolved if JH asked what it was all for and then weigh.
Are you saying that using JH as a character reference and understanding human emotions is as bad as getting used as disposable favor and leverage for inheritance? And did DH suddenly treated JH horribly when DH didn't get what he wanted?
Uhm, he wasn't taking money from JH, or anything related to family and connections. So...what's the deal? And all the progress DH made for himself, went to the drain. JH also never thought how much effort it took for DH to let him in. DH was upfront about his difficulties. Is JH anger valid? I guess? But idk, it didn't need to be this bad, at least to me. Ugh, if I was DH I would disappear, too bad for his family but I'll just disappear. Not just out of shame but just the fact that I became that vulnerable but it was all for nothing, in the end, all that effort was still misunderstood.